Land, Buildings, Equipment and Software, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
capitalized cloud computing costs, additions	$ 3	$ 39	$ 5
us-gaap_CapitalizedComputerSoftwareNet	47	44
capitalized cloud computing costs, accumulated amortization	(6)	(2)
cloud computing costs, net	41	42
amortization expense for cloud computing	$ 4	$ 2	$ 0
capitalized cloud computing costs, useful lives, maximum	5 years
capitalized cloud computing costs, useful lives minimum	3 years